Several of us with 1992+ Bighorns have in the past struggled with the intermittent switch on the windscreen (windshield) wipers only working sometimes, even after replacing the rotary switch. I discovered by accident that I can get mine to work by turning the headlights on and off one or more (maybe 3 or 4) times! My theory is that this may create enough voltage change to get some relay to work. (Of course one could also get a new relay, if that is indeed the issue, but waste money if it is not)